Temporary Brittle Bone Disease

Association with Decreased Fetal

Movement and Osteopenia

M. E. Miller,1 T. N. Hangartner2

1Department of Pediatrics, Wright State University School of Medicine, Dayton, Ohio, USA

2BioMedical Imaging Laboratory, Wright State University School of Medicine, Dayton, Ohio, USA

Received: 26 February 1998 / Accepted: 4 August 1998
Abstract.

Infants who present with multiple unexplained fractures pose a difficult diagnostic dilemma of child abuse versus intrinsic bone disease. Temporary brittle bone disease is a recently described disease characterized by a transient
bone weakness in the first year of life which presents with multiple, unexplained fractures that can be confused with child abuse. The purpose of this study was to determine if there are common, historical features in infants with unexplained fractures that might suggest a basis for the fractures, and to determine if bone density measurements might indicate that such infants have low bone density. Medical records were reviewed in 33 infants who were referred for consultation for multiple unexplained fractures in which the parents and other caregivers denied wrongdoing. In 9 of the infants, radiographic absorptiometry and/or computed tomography bone density studies were performed. In 26 of these infants the diagnosis of temporary brittle bone disease was made. A normal collagen test was found in 17 of the 26 infants studied; 9 infants did not have a collagen test because the diagnosis of osteogenesis imperfecta was considered highly unlikely. In 25 of them there was a history of decreased fetal movement and/or intrauterine confinement. Bone density, as judged by plain X-ray films, was normal in all 26 cases, but when formally measured by radiographic absorptiometry or computed tomography, the bone density
measurements were low in 8 of the 9 infants studied. These findings implicate decreased fetal movement and intrauterine confinement as contributing factors to temporary brittle bone disease and suggest that normal, unconstrained fetal movement during pregnancy is important for normal fetal bone formation. These findings support the model that bone formation and strength are dependent on the mechanical load placed on the bone. The results also demonstrate the usefulness of bone density measurements in evaluating the infant with multiple unexplained fractures to help distinguish nonaccidental injury from intrinsic bone disease.

Infants with multiple unexplained fractures (MUF), in which the parents and other caretakers deny wrongdoing,
pose a difficult diagnostic dilemma [1]. The distinction between intentional injury and intrinsic bone disease is often
not clear, particularly at the time of initial presentation when a documentation of the history and other laboratory studies is incomplete. A wrong disposition in these cases could return a vulnerable infant to abusive parents, or could remove an unintentionally injured infant from parents wrongfully accused of child abuse. One of the most common bone disorders that has been mistaken for intentional injury is osteogenesis imperfecta (OI) [2].

In 1993 Paterson et al. described ‘temporary brittle bone disease’ as another entity that could be mistaken for child abuse. The natural history of temporary brittle bone disease (TBBD) was one of MUF during the first year of life, with no unexplained fractures thereafter [3]. A hallmark of TBBD was a lack of cutaneous injury at the time of injury and on prior examinations in the face of multiple fractures of various ages. Paterson et al. found that there were certain clinical features associated with TBBD including twinning, prematurity, apnea, colic, anemia, and a family history of hyperextensibility. He postulated that a nutritional deficiency such as copper deficiency might be the basis of TBBD, but this has not been confirmed. The present study reports clinical information that suggests decreased fetal movement with bone unloading, often secondary to intrauterine confinement (IUC), as a cause of TBBD, and underscores the importance of bone density measurements in evaluating infants with MUF.

Methods
Since February 1994, one of the authors (MEM) has had infants with MUF referred for clinical evaluation in which child abuse was being considered; the parents and other caretakers denied intentional injury. These cases were evaluated at the request of the parents or their attorney. The present study reports on the clinical features of 33 infants with MUF in which 26 were consistent with TBBD based on the following criteria:

(1) parents and caregivers denied wrongdoing at the time of presentation and throughout the investigation by authorities,

(2) there was no apparent episode(s) of trauma to explain the fractures,

(3) there was no external skin injury such as bruising at the time of presentation or at prior health
care visits,

(4) further evaluation revealed no other evidence of systemic findings that would indicate child abuse—no retinal hemorrhages, no subdural hematomas, no visceral organ damage,

(5) radiographs showed no evidence of metabolic bone disease,

(6) laboratory studies evaluating for metabolic bone disease such as serum calcium and phosphorus and collagen analysis to evaluate for OI were normal.
Histories were obtained and physical examinations were performed in most of the infants; records summarizing these findings were used in the evaluation of other infants. Mothers of infants with TBBD were asked if the movement during the pregnancy was normal, increased, or decreased. If they had had other pregnancies….

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Correspondence to: M. E. Miller, Children’s Medical Center, Dayton,
OH 45404, USA